Listeria outbreak deadliest since 1924, the CDC reports

29 have died of illness linked to cantaloupes

by Elizabeth Weise - Nov. 4, 2011 12:00 AMUSA Today

With 29 people confirmed dead, the listeria outbreak linked to cantaloupes from one Colorado farm is officially the deadliest food-borne illness outbreak in the United States since 1924, according to the Centers for Disease Control and Prevention.

The outbreak comes from Rocky Ford-brand cantaloupes sold by Jensen Farms near Holly, Colo. The cantaloupes were recalled Sept. 14, and no melons under the recall are on store shelves.

The CDC announced the latest death toll Wednesday. A total of 139 people have been reported ill.

The CDC's computerized outbreak-report records go back to 1973, and less formally back to 1967, says Robert Tauxe, deputy director of the CDC's Division of Foodborne, Waterborne and Environmental Diseases. Before that, there was no national system for documenting food-borne illness outbreaks. Instead, doctors have turned to public-health textbooks from the 1900s for accounts of outbreaks.

The deadliest documented outbreak in the United States was in the winter of 1924-25, when typhoid in raw oysters from New York City killed about 150 people, Tauxe says.

The death toll from the new listeria outbreak now surpasses the outbreak in 1985, traced to Mexican-style fresh cheese from Jalisco Products of Artesia, Calif. In that outbreak, 18 adults and 10 newborns died, and 20 women miscarried, according to the CDC.

In the Jensen Farms outbreak, the number of dead continues to rise even weeks after the cantaloupe were recalled, in part because listeria can take as much as two months to cause illness after a contaminated food is consumed. That's because listeria lives within the cells.

"It has some refuge from the immune system, so it can linger and proliferate over a long time," says Ben Silk, an epidemiologist at the CDC who has been leading the listeria investigation.

Another interesting aspect of the outbreak is that there have been so few miscarriages.

It's probably because most of the victims were older and less likely to be pregnant. They ranged in age from 48 to 96, with a median age of 81. Listeria is very dangerous to the developing fetus.